Rotary drive device and a robot arm of a robot equipped therewith

ABSTRACT

A rotary drive device has a fluid-actuated rotary drive which has a drive housing and a drive unit rotatable about a main axis relative to the drive housing. The drive unit contains a pivot piston which divides two drive chambers from one another in the interior of the drive housing, which can be supplied with compressed air fluidic pressure medium controlled by a control fluid channel system, in order to cause a rotational movement of the drive unit. The rotary drive is equipped with a pressure detecting device, which enables pressure detection of the fluid pressure prevailing in the two drive chambers by means of pressure detecting channels formed separately with respect to the control fluid channel system. A robot arm is also proposed, which includes the rotary drive device as an arm joint.

BACKGROUND OF THE INVENTION

The invention relates to a rotary drive device comprising afluid-actuated rotary drive, which has a drive housing and a drive unitrotatable relative thereto about a main axis of the rotary drive by acontrolled fluid application of at least one pivot piston arranged inthe drive housing, whereby a drive shaft of the drive unit connected tothe pivot piston projects from the drive housing at an axial front sideof drive housing with a drive section enabling a force output, and witha control valve arrangement comprising at least one electricallyactuatable control valve, which is fluidically connected via a controlfluid channel system to two drive chambers of the rotary drive separatedfrom one another by the pivot piston in the drive housing, and which isdesigned to control the fluid pressurization of the two drive chambersfor rotation and rotative positioning of the drive unit relative to thedrive housing.

The invention further relates to a robot arm of a robot which has atleast two arm members which are connected with one another in apivotable manner relative to one another by means of an arm joint.

A rotary drive device designed in the aforementioned manner is knownfrom DE 20 2008 003 944 U1. It comprises a fluid-operated rotary drive,which has a drive housing and a drive unit rotatable relative to thedrive housing. The drive unit comprises a drive shaft projecting fromthe front of the drive housing and two pivot pistons non-rotatablyconnected to the drive shaft in the interior of the drive housing, eachdividing two drive chambers from one another. The drive chambers areconnected to a control valve arrangement and can through their actuationbe supplied with compressed air, and thereby controlled, such thatrotational movement of the drive unit relative to the drive housing canbe brought about.

From DE 39 41 255 C2, a rotary drive device is also known in which thedrive shaft of the fluid-operated rotary drive is however combined withonly a single pivot piston to form a drive unit.

DE 10 2010 013 617 B4 discloses a robot of a modular design, which has amovable robot arm which is equipped with at least one arm jointinterconnecting two arm members which are movable relative to oneanother. The arm joint is formed by a rotary drive device comprising anelectrically actuatable rotary drive.

SUMMARY OF THE INVENTION

The invention has for its object to provide a rotary drive device whichallows a very precise rotative positioning of the drive unit and whichis particularly suitable for the realisation of at least one robot armhaving an arm joint.

To solve this problem it is provided in a rotary drive device inconjunction with the above-mentioned features, that a pressure detectingdevice is arranged on the fluid-actuated rotary drive, by which thefluid pressure prevailing in the drive chambers can be detected viapressure detecting channels opening into the two drive chambers anddesigned separately with respect to the control fluid channel system,for enabling a pressure-regulated operating mode of the fluid-operatedrotary drive.

A robot arm of a robot according to the invention comprises at least onearm joint connecting two arm members in a pivotable manner relative toone another, which is formed by a rotary drive device designed in theaforementioned manner, whereby the drive section of the drive shaft andthe drive housing of the fluid-operated rotary drive each have amounting interface for mounting one of the arm members of the robot arm.

According to the invention, the fluid-actuated rotary drive is equippedwith a pressure detecting device, which offers the possibility ofdetecting the fluid pressure prevailing in the two drive chambersseparately from one another. With the help of such pressure detection, apressure-controlled operating mode of the fluid-operated rotary drive ispossible, whereby the rotational movement and the rotational positionsrealisable by the rotational movement can be predetermined based on thefluid pressure building up in the drive chamber. Depending on whether apressure difference is set in favour of the first or the second drivechamber, the drive device rotates in one or the other direction, wherebythe speed of rotation can be influenced by the extent of the pressuredifference. To specify a specific rotational position of the drive unit,an identical fluid pressure can be set in the two drive chambers, whichcan be verified and monitored by means of the pressure detecting device.The aeration and deaeration of the drive chambers taking place for thepurpose of changing the pressure conditions takes place through thecontrol fluid channel system, via which the drive chambers communicatewith a control valve arrangement having at least one electricallyactuatable control valve. The control fluid channel system opens intoeach of the two drive chambers with a working channel. The pressuredetecting device operates particularly precisely because the pressurepickup in the drive chambers does not take place via the control fluidchannel system, but via separate pressure detecting channels, which openinto one of the drive chambers independently of the control fluidchannel system and its working channels. Short-term pressurefluctuations, which occur in particular in a transition between anaeration state and a deaeration state in the working channels, thus haveno effect or at least only a minimal effect on the detected fluidpressure, so that the drive unit is rotatable and rotativelypositionable with high accuracy.

Advantageous further developments of the invention are described in thedependent claims.

The drive chambers are expediently bounded radially on the outside by aperipheral side wall of the drive housing, whereby the pressuredetecting channels pass through this peripheral side wall, in particularin a radial direction with respect to the main axis. Each pressuredetection channel opens at the radial inner circumferential surface ofthe peripheral side wall facing the main axis in one of the drivechambers.

The pressure detecting device is preferably arranged on the outercircumferential surface of the peripheral side wall of the drive housingfacing radially away from the main axis. The pressure detecting devicethus sits directly on the drive housing with a particularly smalldistance from the drive chambers.

The pressure detecting device expediently contains, for each drivechamber, its own pressure sensor, which is connected to the pressuredetection channel opening into the relevant drive chamber. Preferably,each pressure sensor is inserted or plugged from the outside of thedrive housing into the associated pressure detection channel, for whichpurpose it preferably has a pressure pickup connection piece axiallyimmersed in the pressure-detection channel.

The pressure detecting channels preferably open into the drive chamberswith inner channel entrances such that these inner channel entrances lieoutside a pivoting range that can be traversed by a wing section of thepivot piston when the pivot piston executes a pivoting movement thatcauses the drive unit to rotate.

The inner channel entrances of the pressure detecting channels arearranged in particular on this side and the other side in the vicinityof a partition wall element which, together with the pivot piston,subdivides a housing interior formed in the drive housing into the twodrive chambers in a circular contour.

The partition wall element is in particular designed such that it actsas a stop element for specifying a maximum pivot angle of the rotatingpiston through interaction with the wing section of the pivot piston.The inner channel entrances of the pressure detecting channels arearranged adjacent to the partition wall element in regions of the drivechambers, which are outside of the pivoting range of the wing sectiondefined by the maximum pivot angle of the pivot piston. This ensuresthat each pressure detection channel always communicates with one andthe same drive chamber in each pivoting position of the pivot piston.

The control fluid channel system expediently opens into each drivechamber with an inner channel entrance of a working channel, wherebythese inner channel entrances are each arranged on one of two end wallsaxially delimiting the drive chambers of the drive housing of the rotarydrive, in particular on the same axial end wall.

It is advantageous if the pressure detecting device is arranged on asensor holder mounted radially on the outside of the drive housing. Thepressure detecting device is combined expediently with this sensorholder to form an assembly that can be handled as a single unit duringassembly of the rotary drive device.

In an advantageous embodiment of the rotary drive device, an electroniccontrol unit electrically connected with the control valve arrangementfor its electric control is arranged on the rotary drive and is equippedwith a pressure regulation unit processing the fluid pressures detectedin the drive chambers for rotational position control of the drive unit.

The electronic control unit is expediently attached to the drive housingof the rotary drive and is thereby combined with the rotary drive toform a drive assembly that can be handled as a single unit. Eachelectrically actuatable control valve of the control valve arrangementreceives the electrical control signals predetermining the operatingstate from the electronic control unit, in particular controlled by thepressure regulation unit integrated into the electronic control unit.

The at least one electrically actuatable control valve, in particular inthe case of each control valve of the control valve arrangement, ispreferably an electrically controllable piezoelectric valve. Inparticular, each piezoelectric valve has at least one bending transduceras a control element which controls the fluid flow to and from the drivechambers. One and the same piezoelectric valve can have only one singlecontrol element or also a plurality of control elements, whereby thelatter offer the possibility of either controlling high flow rates inparallel actuation or else of using each control element for controllingone of the two drive chambers.

Each piezoelectric valve equipped with a bending transducer expedientlyhas a longitudinal shape and is preferably placed in the region of theouter circumference of the drive housing such that the longitudinal axesof all the existing piezoelectric valves are aligned parallel to themain axis of the rotary drive.

The use of piezoelectric valves as control valves allows in aparticularly advantageous manner a proportional fluid control behaviourin the pressure-controlled fluid admission flow of the drive chambers.In this case, the free flow cross-section made available to the drivefluid used for flowing through, in particular compressed air, can beadjusted very easily by continuous variation of the drive voltage.

As an alternative to a piezoelectric type, the control valve arrangementcan also be of an electromagnetic type. Mixed forms of these two typesare also possible.

In particular, if at least one electrically actuatable control valve ofthe control valve arrangement is designed as a piezoelectric valve, itis advantageous if the electronic control unit has a high-voltage stagewhich is designed to provide the high-voltage drive voltage required forthe actuation of the control valve arrangement. The high-voltage stageis thus preferably also a component of the aforementioned driveassembly.

It is advantageous if the rotary drive device contains, as a furthercomponent, an encoder designed to detect the rotation angle of the driveunit, which is expediently arranged on the axial rear side of the drivehousing of the rotary drive. The encoder provides rotational positionsignals with respect to the rotational position of the drive unit, whichcan be used as the basis for the rotational angular positioning of thedrive unit with respect to the drive housing of the rotary drive. Theencoder is expediently connected to the abovementioned electroniccontrol unit, which is designed in this case to evaluate and process theencoder signals.

The encoder preferably comprises a movable encoder unit, which isarranged non-rotatably on a detection section of the drive shaftprojecting on the axial rear side of the drive housing and whichparticipates in the rotational movement of the drive shaft. It furtherincludes a contactless encoder unit fixedly mounted on the drivehousing, cooperating with the movable encoder unit, whereby it is thefixed encoder unit which is electrically connected to the electroniccontrol unit.

It is particularly advantageous if the rotary drive device has apneumatic connection unit attached to the drive housing, which inexternally accessible manner has an aeration connection which isconnectable or connected to an external pressure source, in particular acompressed air source, and a deaeration connection which is connectableor connected to a pressure sink. The control valve arrangement isconnected via an aeration channel with the aeration connection and alsovia a deaeration channel with the deaeration connection. Thus, thesupply and discharge of the pressure medium necessary for the actuationof the rotary drive, in particular formed by compressed air, can takeplace through the pneumatic connection unit. The term “pneumatic” in thepneumatic connection unit is to be understood as representative of usewith any type of pressurised fluid and is not limited to compressed air.

The aeration connection and/or the deaeration connection expedientlyhave a plug connection device for releasably connecting a fluid hosewhich establishes the connection to the pressure source and to thepressure sink.

Preferably, the pneumatic connection unit is equipped with a furtherpressure detecting device which is able to detect the fluid pressurepresent at the aeration connection and/or at the deaeration connection.This opens up diagnostic options, for example, to monitor whether theaeration connection is present at a sufficiently high supply pressureand/or whether the discharged compressed air can flow without backflow.

The electronic control unit is preferably equipped with anelectromechanical interface device, which allows the connection of, inparticular, a serial bus system connected with a superordinateelectronic control device. This electronic control device is preferablyarranged away from the rotary drive device. It is able to coordinate theactuation of the fluid-operated rotary drive with other devices, forexample with one or more other fluid-operated rotary drives. In thelatter case, it is particularly advantageous if a plurality of rotarydrive devices are integrated as arm joints in a robot arm of a robot.

The rotary drive device can be operated in particular with any serialbus system, for example with a so-called “CAN Bus” or with a so-calledEthernet.

The control valve arrangement is expediently attached to the drivehousing and thus, together with the rotary drive, forms a drive assemblythat can be handled as a single unit.

The control valve arrangement is preferably attached to the drivehousing via a valve carrier device carrying it. This allows aparticularly variable positioning of the control valve arrangement onthe drive housing. In addition, there is the advantageous possibilityfor realising the control fluid channel system at least partially in thevalve carrier device, so that the channel arrangement within the drivehousing can be kept very simple.

The valve carrier device is preferably mounted on the axial rear side onthe drive housing of the rotary drive. The valve carrier device ispreferably mounted on the axial rear side on the drive housing of therotary drive.

The control fluid channel system which establishes the connectionbetween the drive chambers and the control valve arrangement ispreferably formed in its entirety without the use of hoselines andpipelines inside the components of the rotary drive device. This resultsin particularly compact dimensions while avoiding damage to the controlfluid channel system by external mechanical influences.

A robot arm according to the invention is expediently a component of arobot and is equipped with a sufficient number of arm joints, which ineach case connect two arm members of the robot arm in a pivotable mannerEach arm joint is formed by a rotary drive device of the type mentionedabove in various manifestations, such that the articulated arm membersare pivotably positionable relative to one another and are angularlypositionable relative to one another in an application-specific mannerΔt the free end of the robot arm sits an end effector positionable byactuation of the robot arm, for example, a gripping device actuatableelectrically or by fluid force. Both on the drive section of the driveunit and on the drive housing of the rotary drive is a mountinginterface for attachment of one of the arm members connected in anarticulated manner by an arm joint. The driving force for pivoting thearticulated arm members is a fluid force provided by the fluidicpressure medium, in particular compressed air, used to actuate the fluidactuated rotary drive.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below with reference to theattached drawing, in which:

FIG. 1 shows a preferred embodiment of the rotary drive device accordingto the invention in a perspective rear view,

FIG. 2 shows the rotary drive device from FIG. 1 in a furtherperspective view from a different viewing angle, whereby the endsections of two arm members of a robot arm are indicated in dot-dashedlines, which are fastened to the rotary drive device for forming a robotarm,

FIG. 3 shows a longitudinal cross section of the rotary drive deviceaccording to section line from FIG. 5,

FIG. 4 shows a further longitudinal cross section of the rotary drivedevice according to section line IV-IV from FIG. 5,

FIG. 5 shows a cross section of the rotary drive device according tosection line V-V of FIG. 1,

FIG. 6 shows a further cross section of the rotary drive deviceaccording to section line VI-VI from FIG. 1 and

FIG. 7 shows an isometrically exploded view of the rotary drive devicefrom FIGS. 1 to 6.

DETAILED DESCRIPTION

The figures show a section of a robot arm generally designated byreference numeral 1. The robot arm 1 has a plurality of arm members 2 a,2 b, indicated only by dot-dashed lines, which are always connected inpairs by an arm joint 3 of the robot arm 1. The arm joint 3 is formed bya rotary drive device 4 which is shown in most of the figures of thedrawing without the arm members 2 a, 2 b.

The use of the rotary drive device 4 as an arm joint 3 in a robot arm 1is particularly advantageous, but in no way represents the onlypossibility of use for the rotary drive device 4. The same can be usedfor any arbitrary application that involves rotating and/or rotationalangular positioning of two components relative to one another. Forexample, the rotary drive device 4 can be used for rotating and/orrotationally positioning two machine parts of a production plant or apackaging machine. This list is not exhaustive.

The rotary drive device 4 includes a fluid operated rotary actuator 5.It is operated using a pressurised drive fluid, which may be liquid orgaseous, and which is preferably compressed air. The description of thepreferred embodiment is based on an operation with compressed air.

The rotary drive 5 has a longitudinal extension with a centrallongitudinal axis represented below as the main axis 6.

The rotary drive 5 has a drive housing 7, in which a housing interior 8is formed. The main axis 6 forms the centre of the housing interior 8.The housing interior 8 is delimited radially outside by a side wall 12of the drive housing 7 extending peripherally around the main axis 6,which expediently has a circular cylindrical outer contour.

The housing interior 8 is expediently designed circular cylindricallyand arranged coaxially to the main axis 6.

The housing interior 8 is delimited at the two opposite end faces on theone hand by a front end wall 13 and on the other hand by a rear end wall14 of the drive housing 7. By way of example, the peripheral side wall12 is integrally formed with the rear end wall 14, so that a cup-likestructure results, while the front end wall 13 is in this respectseparately formed and secured by fixing screws or other fastening meansto the peripheral side wall 12.

The drive housing 7 has an axial front side 15 arranged in front of theend wall 13 and an axial rear side 16 which is opposite to the rear endwall 14 relating thereto.

A drive shaft 17 of the rotary drive 5 extends coaxially through thedrive housing 7, whereby the longitudinal axis of the drive shaft 17coincides with the main axis 6. The drive shaft 17 is rotatable relativeto the drive housing 7 about the main axis 6 as a rotation axis, wherebya bearing device 18 is in each case provided for pivotal mounting on thetwo end walls 13, 14, which is in particular a rolling contact bearingdevice. The drive shaft 17 is supported in a smoothly rotatable positionby the bearing device 18 and at the same time is supported in a radialand axial direction in relation to the main axis 6 relative to the drivehousing 7.

The drive shaft 17 is part of a drive unit 22, of which a pivot piston23 arranged in the housing interior 8 is also a part. The pivot piston23 is non-rotatably connected to the drive shaft 17, for example bybeing attached with an internal toothing on an outer toothing of thedrive shaft 17, as can be seen in FIG. 5.

Assisted by the pivot piston 23, the housing interior 8 is subdividedinto a first drive chamber 24 and a second drive chamber 25 in afluid-tight manner. A first working channel A opens into the first drivechamber 24, and a second working channel B opens into the second drivechamber 25, each with an inner channel entrance 26.

Preferably, the two inner channel entrances 26 are arranged on the rearend wall 14, which is penetrated by the two working channels A, B inparticular in the axial direction.

A controlled fluid admission flow of the two drive chambers 24, 25 andthus of the pivot piston 23 with the drive fluid is possible through theworking channels A, B, in order to cause a rotative drive movement 27 ofthe drive unit 22 about the main axis 6 as a rotation axis, indicated bya double arrow. The direction of rotation is predetermined by thepressure difference existing between the two drive chambers 24, 25. Bysetting an equally high pressure, the drive unit 22 can be heldnon-rotatably relative to the drive housing 7 in any arbitraryrotational position.

The drive movement 27 can be tapped on a drive section 17 a of the driveshaft 17, which projects from the drive housing 7 on the axial frontside 15.

On the drive section 17 a, a first mounting interface 28 a is arranged,on which a component to be moved rotatively can be fixed. By way ofexample, one arm member 2 a of the two arm members 2 a, 2 b is attachedto the first mounting interface 28 a.

The first mounting interface 28 a may be formed directly on the driveshaft 17, but is preferably part of a separate interface body 29 whichis attached to the drive section 17 a, for example by a screwconnection.

The drive movement 27 is limited to a rotation angle which is smallerthan 360 degrees. The maximum rotation angle is for example 270 degrees.The drive movement 27 can optionally be oriented both clockwise andcounterclockwise.

In order to generate the torque which causes the drive movement 27, thepivot piston 23 has a wing section 23 a, which protrudes on one sidefrom the drive shaft 17 in a radial direction relative to the main axis6. The pivot piston 23 preferably also has a bushing section 23 b, whichis coaxially penetrated by the drive shaft 17 and is fixed non-rotatablyon the drive shaft 17 in the manner described above. The pivot piston 23is provided on its outer surface with at least one seal 23 c, whichslidably abuts under seal against the inner surface of the drive housing7 bounding the housing interior 8.

The section of the seal 23 c extending in the housing interior 8 next tothe wing section 23 a along the radial outer circumference of thebushing section 23 b is slidably in sealing contact with a partitionwall element 32 which is fixed in the housing interior 8 with a radialdistance from the main axis 6. The partition wall element 32 issurrounded by a partition wall seal 32 a, which sealingly abuts not onlythe seal 23 c of the pivot piston 23 but also the radial innercircumferential surface 12 a of the peripheral side wall 12 and theaxial inner surface of the two end walls 13, 14. In this way, thepartition wall element 32 and the pivot piston 23 jointly delimit thetwo drive chambers 24, 25, which are partial chambers of the housinginterior 8.

The pivot piston 23 can be driven by a controlled fluid admission flowof the two drive chambers 24, 25 to a pivoting movement 33 visualised bya double arrow with the main axis 6 as a pivot axis, from which thedrive movement 27 directly results, which can be picked up at the drivesection 17 a.

The partition wall element 32 expediently also functions as a stopelement for specifying a maximum pivot angle of the pivot piston 23. Forthis purpose, the partition wall element 32 has abutment sections 34projecting on both sides of the partition wall seal 32 a in thecircumferential direction of the main axis 6, which are oriented in thedirection of the pivoting movement 33 and against which the pivot piston23 with its wing section 23 a can impinge in order to specify twoopposite end positions of the pivotal movement 33. A maximum pivot angleof the pivot piston 23 is mechanically predetermined by the abutmentsection 34, which is smaller than 360 degrees.

For fastening the other arm member 2 b of the two arm members 2 a, 2 b,a second mounting interface 28 b is formed on the outside of the drivehousing 7, in particular on the outside of the peripheral side wall 12.The same comprises in the embodiment a plurality of mounting holes forscrew mounting the respective arm member 2 b.

In another application of the rotary drive device 4, any arbitrarymachine part may be attached to the second mounting interface 28 b.

For controlled fluid admission flow of the two drive chambers 24, 25,the rotary drive device 4 is equipped with an electrically actuatablecontrol valve arrangement 35. This control valve arrangement 35comprises at least one electrically actuatable control valve 36, wherebyit is expedient if the control valve arrangement 35 has a plurality ofsuch electrically actuatable control valves 36, as apply to theillustrated embodiment.

The control valve arrangement 35 is fluidically connected to the twodrive chambers 24, 25 via a control fluid channel system 37, theessential components of which are apparent in particular from FIG. 6.The two working channels A, B belong to the control fluid channel system37 and each form a channel end section of the control fluid channelsystem 37.

The control valve arrangement 35 is capable of controlling, on the onehand, the aeration and, on the other hand, the deaeration of each drivechamber 24, 25. During aeration, a supply of drive fluid into therespective drive chamber 24, 25 takes place, during deaeration, drivefluid is discharged from the respective drive chamber 24, 25 fordepressurisation.

The control valve arrangement 35 is also connected via at least oneaeration channel 38 to an aeration connection 38 a. In addition, it isconnected via at least one deaeration channel 39 to a deaerationconnection 39 a. The aeration connection 38 a and the deaerationconnection 39 a are located on the outside of the rotary drive device 4,whereby the aeration connection 38 a enables a fluidic communicationwith a pressure source P, in particular designed as a compressed airsource, and the deaeration connection 39 a enables a fluidiccommunication to a pressure sink R, in particular formed by thesurroundings.

The two connections 38 a, 39 a are expediently equipped with hoseconnection devices, each of which enables the releasable connection of afluid hose leading to the pressure source P or to the pressure sink R,respectively. By way of example, the connections 38 a, 39 a are orientedperpendicular to the main axis 6.

The control valve arrangement 35 is mounted on the drive housing 7 ofthe rotary drive 5 and combined in this way with the rotary drive 5 toform an in particular self-supporting drive assembly 42 which can behandled as a single unit.

Expediently, the drive assembly 42 also comprises a valve carrier device43 to which the control valve arrangement 35 is preferably solelyattached and by which the control valve arrangement 35 is fixed to thedrive housing 7 of the rotary drive 5.

Preferably, each control valve 36 is attached to the valve carrierdevice 43, so that it is supported by the same and is fixed stationarilywith respect to the drive housing 7 by means of the valve carrier device43.

It has proved to be particularly advantageous if the valve carrierdevice 43 has a channel plate 44 penetrated by the control fluid channelsystem 37 and preferably also by the aeration channel 38 and thedeaeration channel 39, to which the control valve arrangement 35 isfastened independently of the drive housing 7.

The channel plate 44 is arranged on the axial rear side 16 of the drivehousing 7 and oriented in such a way that its panel plane projectsperpendicular to the main axis 6.

The channel plate 44 has one or more edge sections 45 radiallyprojecting beyond the drive housing 7, to each of which at least one ofthe plurality of control valves 36 is attached so as to be fluidlyconnected to the control fluid channel system 37 in the channel plate44.

According to a preferred exemplary embodiment realised in theillustrated embodiment, the valve carrier device 43 comprises aplurality of cup-shaped structures designated as valve housing cups 46which are respectively fixed to one of the edge sections 45 of thechannel plate 44 and in which at least one of the control valves 36 isincorporated.

Each valve housing cup 46 has a mounting flange 48 at a first axial endsection 47 a, with which it is attached under seal to the front end faceof the edge section 45 pointing towards the axial front side 15 and issecured by means of fixing screws 49 or other fastening means on thechannel plate 44, in particular in a detachable manner. The valvehousing cup 46 is frontally intrinsically open at the first axial endsection 47 a and closed in the assembled state by the edge section 45 ofthe channel plate 44.

Each valve housing cup 46 projects away from the channel plate 44 in afinger-like manner toward the axial front side 15 and terminates freelywith a second axial end section 47 b opposite the channel plate 44. Atthis second axial end section 47 b, the valve housing cup 46, which isopen at the first axial end section 47 a, has a cup base 52.

Each control valve 36 is supported by a second axial end section 53 b onthe inner surface of the cup base 52 and is thereby pressed against thechannel plate 44 with its opposite first end section 53 a. In this way,each control valve 36 is immovably fixed to the valve carrier device 43in the axial direction of the main axis 6.

Expediently, the cup base 52 is provided with one or more apertures 59through which electrical connection contacts of each control valve 36protrude, which are contacted with a printed circuit board 54 attachedto the outside of the cup base 52.

Each printed circuit board 54 is designed with at least oneelectromechanical interface device 54 a, which is designed to supplyelectrical control signals for the operational control of the controlvalves 36.

Each control valve 36 has in particular frontally at its first axial endsection 53 a one or more controllable valve openings 55 whichcommunicate with the control fluid channel system 37 running in thechannel plate 44 via a respective connecting channel 56 opening out atthe rear end face of the edge section 45.

In addition, the interior 57 of at least one valve housing cup 46hereinafter referred to as aeration cup 46 a is connected via anaeration opening 38 b with the aeration channel 38 running in thechannel plate 44, and the interior 57 of at least one valve housing cup46 hereinafter referred to as a deaeration cup 46 b is also connectedvia a deaeration opening 39 b with the deaeration channel 39 running inthe channel plate 44. The aeration opening 38 b and the deaerationopening 39 b respectively open in the region of the open first axial endsection 47 a of a valve housing cup 46 on the end face of the channelplate 44 facing the axial front side 15 and thus are in directcommunication with the interior 57.

The rotary drive device 4 of the preferred illustrated embodimentcomprises an aeration cup 46 a and two deaeration cups 46 b. This numbermay vary, whereby however there is at least one of each type of cup.

The interior 57 of each valve housing cup 46 is in continuous fluidiccommunication with the interior 58 of each control valve 36 arrangedtherein. Each control valve 36 has in its interior 58 at least onecontrol element 62 movable by electrical activation, which acts on amovable valve member 62 a or forms the same directly. By appropriateelectrical control, the position of the control element 62 and thus theposition of the valve member 62 a can be changed in order to eitherclose an associated controllable valve opening 55 or to enable a fluidpassage.

Thus, each control valve 36 is able to separate the working channel A orB, connected to it via the control fluid channel system 37, from theinterior space 57 of the associated valve housing cup 46 or to connectwith this interior 57, in this way, depending on whether it is anaeration cup 46 a or an deaeration cup 46 b, it is able to either aerateor deaerate the associated working channel A or B and thus the connecteddrive chamber 24, 25, or to shut this off for blocking the drive fluidtherein.

It is possible to connect the several control valves 36 contained in onand the same valve housing cup 46 to the same working channel A or B byappropriate design of the control fluid channel system 37, or to connectthe one control valve 36 to the first working channel A and the othercontrol valve 36 to the second working channel B. The correspondingselection is made in particular as a function of the flow rate to bemanaged.

The channel plate 44 is expediently subdivided in a joining plane 63,which is perpendicular to the main axis 6, into two first and secondchannel plate bodies 44 a, 44 b, each plate-shaped. The control fluidchannel system 37 extends in the joining plane 63 and is formed bygroove-shaped recesses formed in one and/or the other channel plate body44 a, 44 b, which are sealed to the surroundings by the other channelplate body 44 b, 44 a with the interposition of a sealing mask 64.

The aeration connection 38 a and the deaeration connection 39 a areexpediently formed together in a pneumatic connection unit 65, which isarranged in the region of the axial rear side 16 of the drive housing 7and which is expediently also a component of the drive assembly 42. Itconsists for example of a block-shaped body, which is penetrated by theaeration channel 38 and the deaeration channel 39 and which is attachedto the channel plate 44, such that both the aeration channel 38 and thedeaeration channel 39 in the channel plate 44 continue to be constantlyfluidically connected to at least one of the interiors 57 of the valvehousing cup 46.

The term “pneumatic” in the pneumatic connection unit 65 is to beunderstood as representative of use with any type of pressurised fluidand is not limited to compressed air. This is merely to express that theconnection unit 65 forms a fluidic interface, at which the drive fluidis fed into the rotary drive device 4 or discharged therefrom.

The pneumatic connection unit 65 is formed integrally with the channelplate 44 and in particular with one of the two channel plate bodies 44a, 44 b in a non-illustrated embodiment.

It is considered particularly advantageous if the pneumatic connectionunit 65 is a separate component with respect to the valve carrier device43, which applies to the illustrated embodiment.

By way of example, the pneumatic connection unit 65 is integrated,relative to the axial direction of the main axis 6, between the rear endwall 14 of the drive housing 7 and the channel plate 44 of the valvecarrier device 43. This has the advantage that the rear side 66, whichis axially averted away from the rotary drive 5 of the valve carrierdevice 43 and in particular of the channel plate 44, is available forthe attachment of other components of the drive assembly 42. Inprinciple, it would certainly be possible to mount the valve carrierdevice 43 directly to the drive housing 7 and to arrange the pneumaticconnection unit 65 on the rear side 66 of the valve carrier device 43.

The control fluid channel system 37, which connects the two drivechambers 24, 25 to the control valve arrangement 35, is expedientlyformed in its entirety within the drive assembly 42 without hoselines orpipelines being involved. This prevents damage and facilitates externalcleaning. In addition, the drive assembly 42 can be assembled in thisway during its manufacture quickly and error-free.

Each control valve 36 of the control valve arrangement 35 is expedientlyarranged at least partially in the region of the peripheral outercircumferential surface 67 of the drive housing 7 which points radiallyoutward with respect to the main axis 6. Preferably, the control valves36 each extend at least partially along the peripheral side wall 12.

Due to the pneumatic connection unit 65 integrated between the valvecarrier device 43 and the drive housing 7, the channel plate 44 isarranged at an axial distance from the drive housing 7. The controlvalves 36 projecting from the channel plate 44 toward the axial frontside 15 thus have a longitudinal section associated with their firstaxial end section 53 a, which extends along the axial distance betweenthe channel plate 44 and the drive housing 7 and to which a furtherlongitudinal section of the control valve 36 connects, which extendsfrom the axial rear side 16 axially along the radial outercircumferential surface 67 of the drive housing 7, whereby the controlvalve 36, however, ends at an axial distance in front of the axial frontside 15 of the drive housing 7.

Thus, there is a configuration in which each control valve 36 projectsbeyond the axial rear side 16 of the drive housing 7, but at the sametime the drive housing 7 projects beyond the control valves 36 in theregion of its axial front side 15.

The aforementioned embodiments relating to the control valves 36 applyin accordance for the valve housing cup 46 accommodating the controlvalves 36.

According to an embodiment not illustrated, the control valves 36 extendover the entire axial length of at least the peripheral side wall 12 ofthe drive housing 7 and in particular of the entire drive housing 7.

The control valves 36 are arranged so that there is only a very smallradial distance to the peripheral side wall 12. As a result, the driveassembly 42 has very small transverse dimensions.

According to an embodiment not illustrated, the control valves 36 aredisplaced axially back relative to the drive housing 7 so that they donot overlap the peripheral side wall 12 of the drive housing 7 at all.

The described arrangement of the control valves 36 can be realisedparticularly advantageously in conjunction with control valves 36, whichare designed as piezoelectric valves 36 a, which applies to theillustrated embodiment.

The piezoelectric valves 36 a have a longitudinal shape and are alignedso that their respective longitudinal axis 69 is parallel to the mainaxis 6.

Each piezoelectric valve 36 a comprises at least one lamellar controlelement 62, which is designed as a bending transducer 62 b, which isdeflectable according to the reverse piezoelectric effect for openingand closing an associated controllable valve opening 55, if it iselectrically controlled with a corresponding drive voltage.

Each bending transducer 62 b expediently extends in the longitudinaldirection of the drive housing 7.

At least some, but preferably all control valves 36 of the control valvedevice 35 are preferably designed so that they are independentlyelectrically actuatable.

The control valves 36 of the control valve arrangement 35 are preferablyarranged distributed around the main axis 6. With reference to a medialplane containing the main axis 6, it is expedient to provide that the atleast one aeration cup 46 a is placed on one side and the at least onedeaeration cup 46 b is placed on the other side of this medial plane.

As can be clearly seen in particular from FIG. 3, the valve carrierdevice 43 is preferably fixed to the drive housing 7 by means of fixingscrews 68. The fixing screws 68 exemplarily pass through the channelplate 44, on which they are supported with their screw heads, wherebythey are screwed with their threaded shaft into each internal thread,which is formed in the rear end wall 14 of the drive housing 7.

With the same fixing screws 68, the pneumatic connection unit 65 isexpediently attached. The fixing screws 68 pass through the pneumaticconnection unit 65 provided with corresponding through holes, so thatthe same is clamped between the drive housing 7 and the channel plate 44of the valve carrier device 43.

If the channel plate 44 is composed of a plurality of adjoining channelplate bodies 44 a, 44 b, these two channel plate bodies 44 a, 44 b areexpediently clamped together axially by the fixing screws 68.

In this way, there is a modular design that favours the manufacture andassembly of the individual components of the drive assembly 42.

Expediently, the drive assembly 42 also contains, as a furthermodule-like component, an electronic control unit 72 which iselectrically connected to the control valve arrangement 35 for itselectrical actuation.

The electronic control unit 72 is preferably arranged in the region ofthe axial rear side 16 of the drive housing 7. If the drive assembly 42comprises a valve carrier device 43, which applies to the illustratedexemplary embodiment, the electronic control unit 72 is preferablyplaced on the rear side 66 of the valve carrier device 43.

The electronic control unit 72 is expediently attached directly to thevalve carrier device 43, independently of the drive housing 7. It cantherefore be mounted and demounted if necessary, without also having torelease the valve carrier device 43 from the rotary drive 5.

The preferably detachable fastening of the electronic control unit 72 tothe valve carrier device 43 is effected in particular by means of aplurality of stud bolts 73 with an external thread, which are anchoredin the channel plate 44, and thereby expediently in the second channelplate body 44 b, and protrude backwards away from the drive housing 7over the valve carrier device 43. On these stud bolts 73, the electroniccontrol unit 72 is attached and fixed by means of fastening nuts 74screwed onto the stud bolts 73.

The fixing of the electronic control unit 72 is expediently carried outon a printed circuit board 75 of the electronic control unit 72, whichhas fastening holes through which the stud bolts 73 protrude. Thecircuit board 75 is oriented so that the circuit board plane extendsperpendicular to the main axis 6.

The electronic control unit 72 is connected to the electromechanicalinterface devices 54 a via a first electrical conductor arrangement 76,indicated by dot-dashed lines, which is realised in particular in theform of electric cables, in order to provide the electrical connectionbetween the electronic control unit 72 and the control valve arrangement35, which enables an electrical activation.

The electronic control unit 72 is able to generate at least onevariable-level electrical drive voltage, which is communicated as acontrol signal to the control valve arrangement 35 to operate thecontrol valves 36 as required.

In particular, when the control valves 36 are designed as piezoelectricvalves 36 a, it is advantageous if the electronic control unit 72 has ahigh-voltage stage 77, by means of which a high-voltage drive voltagesuitable for controlling the bending transducers 62 b can be generated.The high-voltage stage 77 is thus also an integral part of the driveassembly 42.

The electronic control unit 72 is designed to enable coordination withrespect to its operation with other electrically actuatable devices, inparticular with other rotary drive devices 4 used as arm joints 3. Forthis purpose, it is equipped with an electromechanical interface device78 to which a serial bus system 82 is connected or connectable, whichestablishes a control-technical connection with a superordinate externalelectronic control device 83, for example by means of electrical cables.

The bus system can alternatively also be designed for parallel signaltransmission with a 1:1 wiring.

The electromechanical interface device 78 is designed in particular suchthat serial bus signals can be looped through in accordance with arrow84 in order to make a connection with a further device to be controlled.

The serial bus system 82 may operate on any arbitrary bus protocol. Theelectronic control unit 72 is designed, for example, to be able toconnect a so-called CAN bus or a so-called IO-Link bus communicationsystem.

Expediently, the rotary drive device 4 is provided with an encoder 85,that is, in other words, a rotary encoder which is designed to detectand evaluate the instantaneous rotation angle between the rotativelymovable drive unit 22 and the drive housing 7. In this way, a detectionof the instantaneous relative rotational position between the drive unit22 and the drive housing 7 is possible. When used as an arm joint 3 of arobot arm 1, the instantaneous relative pivoting position between thetwo arm members 2 a, 2 b can be detected in this way.

Via a second electrical conductor arrangement 86, indicated bydot-dashed lines, the encoder 85 is suitably connected to the internalelectronic control unit 72 of the rotary drive device 4, which isdesigned to command the electrical control of the control valvearrangement 35 on the basis of the electrical output signals of theencoder 85.

The encoder 85 is preferably designed as an incremental encoder. Theencoder 85 can be implemented as an absolute value encoder or as arelative value encoder.

Preferably, the encoder 85 is arranged on the axial rear side 16 of thedrive housing 7. If the rotary drive device 4 has a valve carrier device43 attached to the rear of the drive housing, the encoder 85 isexpediently arranged on its axial rear side 66. The latter applies tothe embodiment.

The drive shaft 17 expediently has an end section 17 b axially oppositethe drive section 17 a, which passes through the rear end wall 14 of thedrive housing 7 and projects on the axial rear side 16 of the drivehousing 7. This rear end section 17 b defines a detection section 87 fora rotary drive device 4 equipped with an encoder 85, which isoperatively connected to the encoder 85. The detection section 87 isexemplified by the free end section of the rear end section 17 b of thedrive shaft 17.

At this detection section 87, a movable encoder unit 85 a isnon-rotatably mounted, which participates in the rotative drive movement27 of the drive unit 22. This movable encoder unit 85 a cooperatescontactlessly in a conventional manner with an encoder unit 85 battached in a fixed location relative to the drive housing 7, which isexemplarily mounted on the valve carrier device 43 and in particular onthe rear side of the channel plate 44. The fixed encoder unit 85 b isconnected to the electronic control unit 72 via the above-mentionedsecond electrical conductor arrangement 86.

The encoder 85 is expediently arranged coaxially with respect to thedrive shaft 17. It can be optimally integrated into the drive assembly42, if the circuit board 75 of the electronic control unit 72 has acentral aperture 88 in which the encoder 85 extends and which ispenetrated in particular by the encoder 85. The aperture 88 ispreferably circular. The encoder 85 can thus be arranged in a commonplane with the electronic control unit 72, whereby this common planeprojects perpendicular to the main axis 6.

Preferably, the electronic control unit 72 also has a main plane ofexpansion perpendicular to the main axis 6, such as the channel plate 44of the valve carrier device 43. This gives the drive assembly 42particularly short length dimensions.

The fluid-operated rotary drive device 4 is preferably equipped with apressure detecting device 91, which is designed to detect the fluidpressure currently prevailing in each of the two drive chambers 24, 25.The detected pressure values are used in particular for carrying out apressure regulation, with the aid of which the rotary drive movement 27including the rotative positioning of the drive unit 22 can be carriedout or is carried out.

The pressure detecting device 91 is expediently arranged on the rotarydrive 5. As can be seen in particular from FIG. 5, the detection of thefluid pressure prevailing in the drive chambers 24, 25 takes placethrough a pressure detection channel 92 a, 92 b, by which a firstpressure detection channel 92 a opens out into the first drive chamber24 via a first inner channel entrance 93 a and a second pressuredetection channel 92 b opens out into the second drive chamber 25 via asecond inner channel entrance 93 b.

Preferably, the pressure detecting channels 92 a, 92 b are not formed bythe working channels A, B, but are formed as separate fluid channels inthis regard and thus also with respect to the control fluid channelsystem 37. This allows a particularly reliable pressure detection, whichis independent of pulse-like pressure fluctuations that can occur in theworking channels A, B in particular when the control valves 36 switchbetween an aeration process and a deaeration process.

In the illustrated preferred embodiment, the pressure detecting channels92 a, 92 b penetrated the peripheral side wall 12 of the drive housing7, so that the inner channel entrances 93 a, 93 b are located on theexemplary circular cylindrical radial inner peripheral surface 12 a ofthe peripheral side wall 12 enclosing the housing interior 8.

The pressure detecting device 91 is preferably arranged on the radialouter circumferential surface 12 b of the peripheral side wall 12 facingaway from the main axis 6.

The pressure detecting device 91 expediently emerges from the outside ofthe peripheral side wall 12, with a pressure pickup connection 94 ineach pressure detection channel 92 a, 92 b. On the end face of thepressure pickup connection 94 is in each case a pressure pickup aperturefor the prevailing fluid pressure in the associated drive chamber 24,25. In this way, the pressure detection takes place practicallyimmediately in the respective drive chamber 24, 25, which entails a highpressure detection accuracy.

The pressure detecting device 91 expediently contains a separatepressure sensor for each drive chamber 24, 25, so that a first pressuresensor 95 a is associated with the first drive chamber 24 and a secondpressure sensor 95 b is associated with the second drive chamber 25.Each pressure sensor 95 a, 95 b has one of the pressure pickupconnections 94 and is inserted or plugged from outside the drive housing7 in the associated pressure detection channel 92 a, 92 b. Eachinterposed seal prevents undesirable fluid leakage from the drivechambers 24, 25 to the surroundings.

Preferably, the rotary drive device 4 includes an electronic pressureregulation unit 96, to which the pressure detecting device 91 isconnected via a third electrical conductor arrangement 97 indicated by adot-dashed line. The pressure regulation unit 96 is designed inparticular as an integral part of the electronic control unit 72.Accordingly, the pressure regulation unit 96 is located in the region ofthe axial rear side 16 of the drive housing 7 and in particular on therear side 66 of the valve carrier device 43.

The previously described electrical conductor arrangements 76, 86, 97are preferably designed as flexible electrical cables which are laid inthe region of the outer circumference of the rotary drive 5.

The pressure detecting device 91 is expediently arranged on a sensorholder 98 mounted radially on the outside of the drive housing 7. Thesensor holder 98 is attached to the radial outer circumferential surface12 b of the peripheral side wall 12 and fixed there in particular byfixing screws. In the sensor holder 98, which is preferably made ofplastic material, a receiving section 99 is preferably formed for eachpressure sensor 95 a, 95 b, which receives and holds the associatedpressure sensor 95 a, 95 b. The pressure sensors 95 a, 95 b areexpediently combined with the sensor holder 98 to form an assembly thatcan be handled as a single unit when it is mounted on the rotary drive5.

As can be clearly seen in particular from FIG. 4, both the inner channelentrances 26 of the two working channels A, B and the inner channelentrances 93 a, 93 b of the two pressure detecting channels 92 a, 92 bare placed in the housing interior 8 in such a way that they are outsidethe pivoting range, which is passed over by the wing section 23 a of thepivot piston 23 during its pivoting movement 33. These inner channelentrances 26, 93 a, 93 b are located correctly on the same side and theother side of the partition wall seal 32 a, immediately adjacent to thepartition wall element 32.

Each of the two inner channel entrances 93 a, 93 b of the pressuredetecting channels 92 a, 92 b is expediently located in a region, pastwhich one of the two abutment sections 34 extends. Each abutment section34, together with the radially adjacent circumferential section of theperipheral side wall 12, delimits a section of the associated drivechamber 24, 25, into which one of the pressure detecting channels 92 a,92 b opens out, in order to act as a pressure pickup section 100 inwhich pressure sensing occurs. Since the abutment sections 34 do notinteract sealingly with the wall of the drive housing 7, the abutmentsections 34 are surrounded by the drive fluid located in the respectiveassociated drive chamber 24, 25, which consequently is also present inthe pressure pickup sections 100.

Preferably, the inner channel entrances 26 of the working channels A, Blie in the circumferential direction of the main axis 6 in the same areaas the abutment sections 34, so that they are covered by the same. Sincethe abutment sections 34 are arranged at an axial distance from theaxial end walls 13, 14 of the housing interior 8, a gap is howeverprovided which allows unimpeded inflow and outflow of the drive fluidpreferably in the form of compressed air.

In FIGS. 5 and 6, the fluid flow of the drive fluid which is possiblefor actuating the rotary drive 5 is indicated by flow arrows. Dashedflow arrows illustrate the aeration flow, dotted flow arrows illustratethe deaeration flow.

The pressure regulation unit 96 is designed to adjust the pressuredifference prevailing in the two drive chambers 24, 25 so that the driveunit 22 performs a desired drive movement 27 and/or is positioned andheld in a desired rotational position with respect to the drive housing7. The rotational speed can be influenced by the level of the setpressure difference. At the same level of pressure in the two drivechambers 24, 25, the rigidity of the system can be predetermined by theextent of the pressure level. The encoder 85 provides instantaneousrotation angle information that is processed during pressure regulation.

The rotational positioning of the drive unit 25, which ispressure-controlled in this manner, expediently takes place in theinternal electronic control unit 72 of the rotary drive device 4,whereby the target values are however expediently predetermined by thesuperordinate electronic control device 83. In this way, an optimalcoordination of several rotary drive devices 4 communicating for controlpurposes with the same superordinate control device 83 is possible.

It is advantageous if the pneumatic connection unit 65 is equipped witha further pressure detecting device 101, which is indicated onlyschematically by dot-dashed lines in the drawing and which is designedto detect the fluid pressure, which is present at the aerationconnection 38 a and/or at the deaeration connection 38 b. With the helpof the pressure values thus acquired, in particular diagnostic functionsare possible, for example, verifications as to whether a sufficientlylarge supply pressure is present and/or whether perfect, backflow-freefluid discharge is ensured. In addition, for example, the detection ofthe pressure gradient of the valve characteristic is possible.

The further pressure detecting device 101 is expediently connected tothe electronic control unit 72 via a fourth electrical conductorarrangement 102.

As can be seen in particular from FIG. 4, the drive shaft 17, with itsrear end section 17 b projecting from the drive housing 7 on the axialrear side 16, passes through both the pneumatic connection unit 65 andthe channel plate 44 of the valve carrier device 43 in a rotatablemanner relating thereto.

The drive shaft 17 is expediently traversed in its longitudinaldirection by two fluid channels designated as shaft channels 103 fordifferentiation purposes, which are connected with an annular groove 104formed in the drive shaft 17 in the longitudinal section of the rear endsection 17 b of the drive shaft 17, which projects through the pneumaticconnection unit 65. The longitudinal sections of the aeration channel 38and of the deaeration channel 39 extending through the pneumaticconnection unit 65 each have a branch via which they communicate withone of the two annular grooves 104. In this way, one of the two shaftchannels 103 is constantly connected to the aeration connection 38 a andthe other is constantly connected to the deaeration connection 39 aregardless of the rotational position of the drive shaft 17.

Interface means, not further illustrated in the drawings, are assignedto the shaft channels 103 in the region of the drive section 17 a, towhich further fluid channels can be connected in order to allow afluidic interlinking with, for example, the rotary drive device 4 ofanother arm joint 3. These secondary fluid channels are preferablyformed by elastically bendable fluid hoses. The same can be laidloop-shaped or helically wound in the interface bodies 29.

In the illustrated embodiment, the rotary drive 5 includes only a singledrive stage formed by two drive chambers 24, 25 and a pivot piston 23incorporated therein.

According to a not further illustrated embodiment, however, amulti-stage design is possible in which the rotary drive 5 has at itsdisposal a plurality and in particular two axially adjacent pivotpistons 23 which each separate a separate pair of drive chambers 24, 25from one another and are non-rotatably connected with the same driveshaft 17. With such a design, particularly high torques can begenerated.

What is claimed is:
 1. A rotary drive device comprising a fluid-actuatedrotary drive, which has a drive housing and a drive unit rotatablerelative thereto about a main axis of the rotary drive by a controlledfluid application of at least one pivot piston arranged in the drivehousing, whereby a drive shaft of the drive unit connected to the pivotpiston projects from the drive housing at an axial front side of thedrive housing with a drive section enabling a force output, and with acontrol valve arrangement comprising at least one electricallyactuatable control valve, which is fluidically connected via a controlfluid channel system to two drive chambers of the rotary drive separatedfrom one another by the pivot piston in the drive housing, and which isdesigned to control the fluid pressurization of the two drive chambersfor rotation and rotative positioning of the drive unit relative to thedrive housing, wherein a pressure detecting device is arranged on thefluid-actuated rotary drive, by which the fluid pressure prevailing inthe drive chambers can be detected via pressure detecting channelsopening into the two drive chambers and designed separately with respectto the control fluid channel system, for enabling a pressure-regulatedoperating mode of the fluid-operated rotary drive.
 2. The rotary drivedevice according to claim 1, wherein the pressure detecting channelspass through a peripheral side wall of the drive housing radiallyoutwardly bounding the drive chambers and open into the drive chamberson the inner circumferential surface of the peripheral side wallradially facing the main axis.
 3. The rotary drive device according toclaim 2, wherein the pressure detecting device is arranged on the outercircumferential surface of the peripheral side wall of the drive housingfacing radially away from the main axis.
 4. The rotary drive deviceaccording to claim 1, wherein a separate pressure detection channelopens out into each drive chamber, to which a pressure sensor of thepressure detecting device is connected.
 5. The rotary drive deviceaccording to claim 4, wherein the pressure sensor is plugged from theoutside into the associated pressure detection channel.
 6. The rotarydrive device according to claim 1, wherein the pressure detectingchannels with internal channel entrances open into the drive chambers insuch a way that these inner channel entrances lie outside of a pivotingrange, which can be traversed by a wing section of the pivot pistonduring the pivoting movement of the pivot piston causing the rotation ofthe drive unit.
 7. The rotary drive device according to claim 6, whereinthe pivot piston is arranged in a circular contoured housing interior ofthe drive housing and together with a partition wall element arrangedlikewise in the housing interior subdivides the housing interior in afluid-tight manner into the two drive chambers, wherein the partitionwall element acts as a stop element by interacting with the wing sectionof the pivot piston to specify a maximum pivot angle of the pivot pistonand wherein the inner channel entrances of the pressure detectingchannels are located adjacent to the partition wall element in regionsof the drive chambers which are outside of the pivoting range of thewing section defined by the maximum pivot angle of the pivot piston. 8.The rotary drive device according to claim 1, wherein the control fluidchannel system opens out into each drive chamber with an inner channelentrance of a working channel, wherein the inner channel entrances ofthe working channels are arranged respectively to one of two end wallsof the drive housing of the rotary drive axially delimiting the drivechambers.
 9. The rotary drive device according to claim 1, wherein thepressure detecting device is arranged on a sensor holder mountedradially outside on the drive housing.
 10. The rotary drive deviceaccording to claim 1, wherein an electronic control unit connected withthe control valve arrangement for the electric control thereof isarranged on the rotary drive, which is equipped with an electronicpressure regulation unit processing the fluid pressures detected in thedrive chambers for rotational position control of the drive unit. 11.The rotary drive device according to claim 10, wherein the electroniccontrol unit is arranged on the axial rear side of the drive housingopposite the axial front side.
 12. The rotary drive device according toclaim 10, wherein the at least one control valve of the control valvearrangement is designed as an electrically controllable piezoelectricvalve, wherein the electronic control unit has a high-voltage stage forgenerating a high-voltage drive voltage for the control valvearrangement.
 13. The rotary drive device according to claim 10, furthercomprising an encoder designed to detect the rotation angle of the driveunit, which is arranged on the axial rear side of the drive housing ofthe rotary drive, wherein the encoder has a movable encoder unitarranged on a detection section of the drive shaft protruding on theaxial rear side of the drive housing and a fixed encoder unit attachedto the drive housing and cooperating contactlessly with the movableencoder unit, wherein the fixed encoder unit is electrically connectedto the electronic control unit.
 14. The rotary drive device according toclaim 1, further comprising a pneumatic connection unit attached to thedrive housing, which has, in an externally accessible manner, anaeration connection connectable or connected with an external pressuresource and a deaeration connection connectable or connected to anexternal pressure sink, wherein the control valve arrangement isconnected with both the aeration connection and with the deaerationconnection.
 15. The rotary drive device according to claim 14, whereinthe pneumatic connection unit is equipped with a further pressuredetecting device, by which the fluid pressure pending at the aerationconnection and/or at the deaeration connection can be detected.
 16. Therotary drive device according to claim 1, wherein the electronic controlunit has an electromechanical interface device for connecting a bussystem connected to a superordinate electronic control device.
 17. Therotary drive device according to claim 16, wherein the bus system is aserial bus system.
 18. The rotary drive device according to claim 1,further comprising a valve carrier device carrying the control valvearrangement and attached to the drive housing.
 19. A robot arm of arobot, comprising at least two arm members connected to one another bymeans of an arm joint in a relatively pivotable manner, wherein the armjoint is formed by a rotary drive device which comprises afluid-actuated rotary drive, which has a drive housing and a drive unitrotatable relative thereto about a main axis of the rotary drive by acontrolled fluid application of at least one pivot piston arranged inthe drive housing, whereby a drive shaft of the drive unit connected tothe pivot piston projects from the drive housing at an axial front sideof the drive housing with a drive section enabling a force output, andwith a control valve arrangement comprising at least one electricallyactuatable control valve, which is fluidic ally connected via a controlfluid channel system to two drive chambers of the rotary drive separatedfrom one another by the pivot piston in the drive housing, and which isdesigned to control the fluid pressurization of the two drive chambersfor rotation and rotative positioning of the drive unit relative to thedrive housing, wherein a pressure detecting device is arranged on thefluid-actuated rotary drive, by which the fluid pressure prevailing inthe drive chambers can be detected via pressure detecting channelsopening into the two drive chambers and designed separately with respectto the control fluid channel system, for enabling a pressure-regulatedoperating mode of the fluid-operated rotary drive, wherein the drivesection of the drive shaft and the drive housing of the fluid-operatedrotary drive each have a mounting interface to which one of the armmembers of the robot arm is attached.